Deliberate mistake: At the beginning, we see the Scorpion King leading his army into battle. However, despite people being stabbed with swords, and slashed, there is no blood on any of the soldiers, nor on their weapons. Kind of hard to believe war was that clean back then. (00:01:40)
Deliberate mistake: According to the DVD version, the Army of Anubis roars in ARABIC. Rather strange for a monstrous army of an ancient Egyptian god... (01:44:15)
Deliberate mistake: When Rick and Imhotep battle man-to-man at the end, in one shot above them you see steam blasting from the side of the screen. Problem is that when the angle changes, it's clear that area is just empty space, so the steam came from nowhere. (The DVD commentary mentions that they always had people with flame-throwers and steam-machines right off-screen to blast fire and smoke to make certain scenes more dramatic).
Answer: He says that it means 'it's as hot as hell'.